java.util.ArrayList#include? returns false incorrectly (9.1.3.0 onwards)

[betesh]

$ rvm jruby 9.1.2.0  do ruby -e "j = java.util.ArrayList.new; j << java.lang.Integer.new(7); puts j.include?(7)"
true
$ rvm jruby 9.1.3.0  do ruby -e "j = java.util.ArrayList.new; j << java.lang.Integer.new(7); puts j.include?(7)"
false

I did a git bisect and traced this to commit 2e47a9d

Environment

• JRuby version: All versions from 9.1.3.0 onwards

• Operating system and platform:

$ uname -a
Linux 4.17.0-041700-generic #201806041953 SMP Mon Jun 4 19:55:25 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Expected Behavior

When I insert a java.lang.Integer into a java.util.ArrayList and pass the corresponding Ruby Fixnum to #include?, I expect it to return true

Actual Behavior

Starting with jruby 9.1.3.0, it returns false

[kares]

interesting find, still I would consider the previous behaviour invalid and not inline with Ruby types.
collections are meant to behave in a similar fashion to Ruby types such as the good-old Array :

$ bin/jruby -e 'a = [ java.lang.Integer.new(1) ]; p a.include?(1); p a.include?(1.to_java); p a.include?(1.to_java(:int))'
false
false
true

previous functionality meant always going through a collection - so include? loops for Java sets etc.
... Enumerables convention is to not re-define include? as is for collection types (Array, Set)

also if you need the previous behaviour you could transplant Enumerable#include? for Collection

[betesh]

I would consider the previous behaviour invalid and not inline with Ruby types

I would expect include? to test whether any of the elements equal the arg. In the example in your comment, the (Ruby) Array does not include the arg because none of its elements are equal to the arg:

$ rvm jruby 9.1.3.0 do ruby -e "j = [ java.lang.Integer.new(7) ]; puts j.include?(7); puts j.first == 7; puts 7 == j.first; puts ([7] & j).inspect"
false
false
false
[]

However, in the case I reported, the equality operator returns true, making the behavior of include? very surprising:

$ rvm jruby 9.1.3.0 do ruby -e "j = java.util.ArrayList.new; j << java.lang.Integer.new(7); puts j.include?(7); puts j.first == 7; puts 7 == j.first; ; puts ([7] & j).inspect"
false
true
true
[7]

[googya]

[16] pry(main)> 7 == java.lang.Integer.new(7)
=> false

7 is not equal as java.lang.Integer.new(7), maybe that's the point

[betesh]

@googya JRuby supports automatic conversion between Java and Ruby types under certain circumstances but not all. However, equality and inclusion should be consistent for any given case, but in the case I reported, they are not.